I agree, definitely need to get a trans cooler on there, the LS4's run consistently hot for some reason, never really understood why other then the fact that the radiator is over half the capacity of a typical LSx radiator and the exhaust system routes under the hood through the center of the engine bay leading to extremely high under hood temps. I used an impala SS police pursuit OEM trans cooler with a combination of OEM hard lines and soft lines, I wanted a nice OEM look and fitment that would be reliable. You can run all OEM lines but the 4t65e upper hard line is alot more expensive then the newer stye wbody lines for the 6 speeds. I saw about a 20-30 degree drop in temps, but even on the hottest of days (90+) i still see roughly 210F cruising with the 3.29 gears. Better then what it was since it used to be touching 230.
good god man, 5-8 hours? lol were you trying to remove it by hand? shouldnt take longer then an hour with the appropriate tools.